Can I get H1B after I140 Approved (6m+) and went on H4 (3yrs)

[AvatarAang]

Hi folks,

I have an approved I-140 from a company A (priority date Oct 2014) and continued to work in that company A on H1B till June 2018. I had used more than 6 years of H1B at the point of leaving the company and had one extension based on the approved I-140.

However, due to a family move and the company not willing to let me work remotely, I changed my status to H4 in order to stay in the same location as my family. I was also unable to find a new employer in the new location, who would be able to sponsor a H1B. At this point, I have been on H4 for 2.5 years. In a few months, my spouse will be moving jobs to a new city where my prospects of finding a job in my field will be much better. 

I would appreciate your inputs and experiences if anyone has been in a similar situation. I have the following specific questions:

1. Will I be able to apply for a H1B extension with a new company B, based on my approved I-140 even after being on H4 for the intervening 3 years?

2. I understand the AC21 requires a 'Same or Similar' job to file for the H1B, how is this same or similar job determination made? Is it based on title, responsibilities and tasks performed or is it based only on the job code? 

3. My job title had been Senior BA, but as the role was under the umbrella of the Finance dept within company A, they had used the internal HR title Finance BA III on the H1B extension. As far as portability to similar or same job, will I now have to look for a BA position within a Finance dept only? Or can I look more broadly for a BA position?

I sincerely appreciate any input or shared experience in this matter. Thanks!